Science-2004-Leroy ebola

DOI: 10.1126/science.1092528, 387 (2004);303 Science et al.Eric M. Leroy

Central African WildlifeMultiple Ebola Virus Transmission Events and Rapid Decline of

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levels under the same conditions. With theaddition of seven further genes recentlyexamined (21), the fraction of genes withsignificantly reduced mRNA levels is 8/16or 50% (95% confidence limits: 27 to73%).

This effect on TFs in DM1 suggests com-parisons with Huntingtons disease (HD) inwhich huntingtin selectively binds and dis-rupts Sp1 (22, 23). However, this protein-protein interaction in HD is more restrictedthan the RNA-protein interaction in DM1,which sequesters many TFs concurrently.Correspondingly, the extent of derangementof gene transcription in HD models (estimat-ed at 2%) (24) is far less than seen in ourDM1 sample (50%).

A common requirement for basic tran-scription factors in different tissues that ex-press DMPK could account for the multisys-temic and multisymptomic nature of DM1findings (e.g., myotonia, myopathy, diabetes,testicular atrophy). Notably, the clinical anal-ogies between DM1 and DM2, in which thelatter has CCUG mRNA expansions (25),may conceivably derive from a commontrans-acting mechanism with trapping and de-pletion of similar or identical TFs.

Other examples of transcriptional dys-regulation in genetic disorders are the tricho-thiodystrophies, a group of autosomal reces-sive diseases (26), and Cockayne syndrome(27). All result from phenotype-specific mu-tations in genes encoding TFIIH, a multicom-ponent complex that has been implicated intranscription and DNA excision repair.Whereas repair defects explain the skin pho-tosensitivity seen in a subset of patients, otherdisease phenotypes have been attributed totranscriptional defects (26). Deletion of thevariable-number tandem-repeat structure thatbinds transcription repressor YY1 leads totranscriptional derepression in the respectivechromosomal band, to result in facioscapulo-humeral muscular dystrophy (28). This shortlist of genetic disorder transcription syn-dromes (29) can now perhaps be extended.

References and Notes1. J. D. Brook et al., Cell 68, 799 (1992).2. G. Jansen et al., Nature Genet. 13, 316 (1996).3. A. D. Otten, S. J. Tapscott, Proc. Natl. Acad. Sci.

U.S.A. 92, 5465 (1995).4. N. A. Timchenko et al., J. Biol. Chem. 276, 7820

(2001).5. A. V. Philips, L. T. Timchenko, T. A. Cooper, Science

280, 737 (1998).6. A. Mankodi et al., Mol. Cell 10, 35 (2002).7. N. Charlet-B et al, Mol. Cell 10, 45 (2002).8. R. P. Junghans, A. Ebralidze, B. Tiwari, Neurogenetics

3, 59 (2001).9. K. L. Taneja, M. McCurrach, M. Schalling, D. Housman,

R. H. Singer, J. Cell Biol. 128, 995 (1995).10. B. M. Davis, M. E. McCurrach, K. L. Taneja, R. H. Singer,

D. E. Housman, Proc. Natl. Acad. Sci. U.S.A. 94, 7388(1997).

11. Appropriate conditions for in vitro binding are insuf-ciently understood to replicate the selectivity of theTF binding process that occurs in vivo (Fig. 1). Weobserve only nonselective binding of puried TF in

vitro with all RNAs, whether mutant RNA or heter-ologous unrelated RNAs (12). The same discordancecan be inferred for conditions used for CUGBP bind-ing in vitro (31) that fail to reproduce the selectivityfor mutant versus wild-type RNA that is evident invivo (4, 12), (Fig. 1A).

12. A. Ebralidze et al., unpublished observations.13. M. Nicolas, V. Noe, K. B. Jensen, C. J. Ciudad, J. Biol.

Chem. 276, 22126 (2001).14. T. Kimura et al., Neurosci. Lett. 295, 93 (2000).15. GI: 479168 (32) with MatInspector V2.2 software

(33).16. M. E. Massari, C. Murre, Mol. Cell. Biol. 20, 429 (2000).17. Experimental details are available as supporting ma-

terial on Science Online.18. K. S. Rajavel, E. F. Neufeld, Mol. Cell. Biol. 21, 5512

(2001).19. Although mutant RNA double-strand hairpins of

CUG-repeat domains have been noted in vitro byelectron microscopy, and binding of CUGBP in vitroat their single-strand junctions (31), in vitro bindingstudies may be vulnerable to overinterpretation forthe in vivo setting [compare note (11)]. In vivo mu-tant RNP extracted from cells has yet to be studiedstructurally in this fashion.

20. We apply the same standard of 30% change forsignicantly disturbed transcription as used in theHD study (24).

21. Seven additional genes were recently studied, ofwhich three were signicantly suppressed and fourunchanged in mutant RNAexpressing cells. A totalof nine genes have now been tested with TF resto-rations. When Sp1 or Sp3 was overexpressed, full orpartial recovery was seen in three out of four of thedepressed genes, with the fourth presumably re-sponding to depleted TFs not tested, by this model. In

contrast, among the ve genes that were unchangedin mutant RNAexpressing cells, none (0/5) wasstimulated by TF overexpression.

22. A. W. Dunah et al., Science 296, 2238 (2002).23. R. N. Freiman, R. Tjian, Science 296, 2149 (2002).24. R. Luthi-Carter et al., Hum. Mol. Genet. 11, 1911 (2002).25. J. Finsterer, Eur. J. Neurol. 9, 441 (2002).26. E. Bergmann, J. M. Egly, Trends Genet. 17, 279 (2001).27. F. Le Page et al., Cell 101, 159 (2000).28. D. Gabellini, M. R. Green, R. Tupler, Cell 110, 339 (2002).29. W. Vermeulen et al., Cold Spring Harb. Symp. Quant.

Biol. 59, 317 (1994).30. K. Ohshima, S. Kang, J. E. Larson, R. D. Wells, J. Biol.

Chem. 271, 16773 (1996).31. S. Michalowski et al., Nucleic Acids Res. 27, 3534 (1999).32. C. Lorenz, C. Meyer-Kleine, K. Steinmeyer, M. C. Koch,

T. J. Jentsch, Hum. Mol. Genet. 3, 941 (1994).33. K. Quandt, K. Frech, H. Karas, E. Wingender, T.

Werner, Nucleic Acids Res. 23, 4878 (1995).34. We acknowledge the many collegial interactions with

C. Thornton and T. Cooper, who supplied information,materials and advice that assisted many phases ofthe project. Supported by grants to R.P.J. from theMuscular Dystrophy Association and of the NationalInstitute for Arthritis, Muscle, and Skin Diseases(NIAMS) of the NIH.

Supporting Online Materialwww.sciencemag.org/cgi/content/full/1088679/DC1SOM TextFigs. S1 and S2References and Notes

2 July 2003; accepted 19 November 2003Published online 4 December 2003;10.1126/science.1088679Include this information when citing this paper.

Multiple Ebola Virus TransmissionEvents and Rapid Decline ofCentral African Wildlife

Eric M. Leroy,1* Pierre Rouquet,2 Pierre Formenty,3Sandrine Souquie`re,2 Annelisa Kilbourne,4 Jean-Marc Froment,5

Magdalena Bermejo,5 Sheilag Smit,6 William Karesh,4

Robert Swanepoel,6 Sherif R. Zaki,7 Pierre E. Rollin7

Several human and animal Ebola outbreaks have occurred over the past 4 yearsin Gabon and the Republic of Congo. The human outbreaks consisted ofmultiplesimultaneous epidemics caused by different viral strains, and each epidemicresulted from the handling of a distinct gorilla, chimpanzee, or duiker carcass.These animal populations declined markedly during human Ebola outbreaks,apparently as a result of Ebola infection. Recovered carcasses were infected bya variety of Ebola strains, suggesting that Ebola outbreaks in great apes resultfrom multiple virus introductions from the natural host. Surveillance of animalmortality may help to predict and prevent human Ebola outbreaks.

Human Ebola virus (EBOV) infection causeshemorrhagic fever and death within a fewdays (1). The most lethal strains, causing upto 88% mortality, occur in Gabon, the Repub-lic of Congo (RC), and the Democratic Re-public of Congo (DRC) in central Africa, andbelong to the Zaire subtype, which is one offour known EBOV subtypes. Together withMarburg virus, EBOV forms the Filoviridaefamily, a group of enveloped, nonsegmented,negative-strand RNA viruses (2). The ge-nome is 19,000 nucleotides long and bears

linearly arranged genes that encode sevenstructural proteins and one nonstructural pro-tein (3). Human Ebola outbreaks usually oc-cur abruptly from an unidentified source,with subsequent spread from person to person(4). The first three known outbreaks of Ebolaoccurred between 1976 and 1979 in Zaire(now DRC) and Sudan, with 318 (5), 284 (6)and 34 (7) cases, respectively. No furthercases were recognized in Africa until late1994. Since then, EBOV has appeared inhuman beings eight times, in several sub-

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Saharan African countries, including CotedIvoire (8), DRC (1), Uganda (9), RC, andGabon (10). Epidemiologic observationsshowed that chimpanzees were the source ofone human case in Cote dIvoire in late 1994(8) and of an outbreak in Gabon in 1996 (4).The recent high frequency of EBOV out-breaks in central Africa, associated with high

lethality and serious social consequences, hasmade Ebola a major public health priority.Given the very rapid spread of the diseaseand the lack of a vaccine or effective therapy,the cornerstone of management remains theprevention and rapid control of outbreaks.

In the past two years, five human Ebolavirus outbreaks of the Zaire subtype haveoccurred in western central Africa (Gabonand RC), with a total of 313 cases and 264deaths (11). Epidemiologic investigationsshow that these outbreaks resulted from mul-tiple introductions of the virus from differentinfected animal sources (Fig. 1A). The indexcases (mainly hunters) were all infected whenhandling dead animals (gorilla, chimpanzee,or duiker), and subsequent transmission oc-curred by direct person-to-person contact, es-pecially within families. We use the termepidemic chain to designate all cases ofinfection arising from a given index case andthus from a given animal carcass. At least tenepidemic chains were identified between Oc-tober 2001 and May 2003 (Fig. 1A).

To determine whether these outbreaks re-sulted from multiple introductions of a single

viral strain or from separate introductions ofseveral different viral strains, we sequencedthe entire open reading frame of the EBOVglycoprotein (GP) gene in all available infect-ed human samples. Nucleotide sequence vari-ations were found among the viruses respon-sible for the different epidemic chains (Table1) but not between samples from patientsinvolved in a given epidemic chain. On thebasis of genetic analysis, we identified eightviral strains, indicating that the five humanoutbreaks involved distinct animal sourcesand viral strains.

We and local villagers noted a highnumber of animal carcasses in forested ar-eas just before and during the 2001 humanEbola outbreaks in Gabon (Fig. 1B; tableS1). Discovery of dead animals in the forestis normally rare, owing to rapid decompo-sition and the low number of nonpredatorydeaths. Over a period of 8 months, wefound or were informed by local villagersof at least 64 animal carcasses (gorillas,chimpanzees, and duikers) in the outbreakarea of the Zadie region in Gabon (3000km2), with a peak in November and De-

1Institut de Recherche pour le Developpement,UR034, Centre International de Recherches Medicalesde Franceville, BP 769 Franceville, Gabon. 2CentreInternational de Recherches Medicales de Franceville,CIRMF, BP 769 Franceville, Gabon. 3Global Alert andResponse Team (GAR), Department of CommunicableDiseases Surveillance and Response (CDS/CSR), WorldHealth Organization, Geneva, Switzerland. 4WildlifeConservation Society, 2300 Southern Boulevard,Bronx, NY 10460, USA. 5Programme de conservationet utilisation rationnelle des Ecosyste`mes Forestiersen Afrique Centrale (ECOFAC), BP 15115 Libreville,Gabon. 6National Institute for Communicable Diseas-es, Special Pathogens Unit, Private Bag X4, Sandring-ham 2131, South Africa. 7Centers for Disease Controland Prevention, Special Pathogens Branch, 1600Clifton Road, Atlanta, Georgia 30333, USA.

*To whom correspondence should be addressed. E-mail: Eric.Leroy@ird.frThese authors contributed equally to this work.

Fig. 1. (A) Location ofsources of Ebola out-breaks in Gabon and theRepublic of Congo be-tween October 2001 andMay 2003. Stars indicatethe location of the rsthuman case, each infectedby an animal source. Redstars indicate identied orsuspected animal sources.Red and white stars indi-cate unknown sources.The gure also indicatesthe incriminated animal

species and the presumed contact datewith the human index case. TheMekamboand Mbomo outbreaks during October 2001 to May 2002 involved at least sixdifferent animal sources. We found at least one animal source in Entsiami duringthe 2002 outbreak in RC, another animal source in Olloba during the May 2002outbreak in RC, and at least two additional animal sources in the Kelle area (inYembelegoye and Mvoula villages) during the 2003 outbreak in RC. (B) Locationof animal carcasses in Gabon during the 2001 to 2002 outbreak and in RC during

the 2002 to 2003 outbreak. Animal carcasses were precisely located by us or local villagers by using global positioning satellite technology.

Table 1. Nucleotide differences between sequences of the EBOV GP gene identied during Ebola outbreaks in Gabon and the Republic of Congo between October 2001and May 2003. The table gives the names of identied epidemic chains and reports the number of viral sequences obtained in each chain. See (12).

Epidemic chainNucleotide position

247 543 795 1147 1201 1239 1240 1271 1476 1500 1540 1578 1584 1610 1684 2135

Mendemba A (Oct 01) 7 available sequences G C A A A C T T G T T T G A A TMendemba B (Oct 01) 10 available sequences G C A A A C T T G T T T G G A TEkata (Nov 01)Olloba (Dec 01) 1 available sequence G C A A A C T T G T T T A A A CEkata (Dec 01)Etakangaye (Dec 01) 1 available sequence G T G G A C T T G T T T G G A TMakokou (Dec 01) 2 available sequences G C A A A C C T G T T T G G A TEntsiami (Jan 02) 1 available sequence G C A A G C T T A T T T A A A TOlloba (May 02)Yembelengoye (Dec 02) 8 available sequences C G C C C A A AMvoula (Jan 03) 1 available sequence A C A G A T T C G T T T A A G

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cember 2001; most were gorillas (36; tableS1). Considering that we have observedthat a gorilla carcass decomposes complete-ly within one month in the tropical forestand that the carcasses were found in thevicinity of villages (within 2 hours walkingdistance), hundreds or even thousands ofanimals may have died in the thinly popu-lated 3000 km2 of this forest region.

Gorilla (Gorilla gorilla) population cen-suses before and after the Kelle outbreak in2003 in RC showed marked declines after theoutbreak (Table 2). Indices of the presence ofgorilla and duiker (Cephalophus spp.)sighting, hearing, and smelling the animalsby trained trackers, and seeing dung, trails, ornestsfell by 50% between 2002 and 2003in the 320-km2 Lossi sanctuary (Table 2).Similarly, chimpanzee (Pan troglodytes) in-dices declined by 88%. Although a decline inindices does not indicate a similar decline inpopulation densities, it is a robust indicator ofa corresponding population decline (12). Cor-roborating this observation, eight groups ofgorillas, 143 individuals in all, that had beenmonitored almost daily for 10 years in a35-km2 region of the Lossi sanctuary, disap-peared between October 2002 and January2003. These animals have not been seensince, neither within the sanctuary nor else-where. Together, these data indicate temporaland spatial overlaps between human Ebolaoutbreaks and increased mortality amonglarge wild mammals (Fig. 1, A and B). Our

data also confirm that Ebola outbreaks occurabruptly, exterminating exposed animal pop-ulations very rapidly and very locally (groupsliving in other parts of the sanctuary werebarely affected). The duiker populations inthe areas covered by our study may recoverrapidly after an outbreak, owing to this spe-cies rapid reproductive cycle. In contrast, theslow reproductive cycle of the great apes,together with hunting and poaching, may leadto their extinction in western central Africa.This last observation is supported by recentdata indicating that ape populations in Gabondeclined by more than half between 1983 and2000 (13). These findings are also consistentwith those of a study conducted in the TaForest of Cote dIvoire, in which 11 of 43members of a wild chimpanzee group disap-peared in November 1994. One chimpanzeewas positive by EBOV-specific immunohis-tochemical staining (14).

Using a combination of antigen detection,serology, DNA amplification, sequencing,immunohistochemical staining, and virus iso-lation, we confirmed that the gorillas, chim-panzees, and duiker carcasses were indeedinfected by EBOV (Table 3; Fig. 2). In total,ten gorillas, three chimpanzees, and oneduiker tested positive. Of interest, all muscletissues were negative for EBOV-specific im-munoglobulin G (IgG), indicating that theanimals had died without developing specificIgG responses, similar to the situation in hu-man infections in which a fatal outcome is

characterized by impaired humoral responsesand a failure to generate specific IgG (15).

Deaths in wildlife tended to precede andto be linked to human infections. For exam-ple, we detected EBOV in gorilla and chim-panzee carcasses in early December 2002 atthe Lossi sanctuary, and the first human casesin the associated outbreak (Yembelengoyeand Mvoula, 2003) appeared at the end of thatmonth. In addition, serum from the indexcase (a survivor) in the last human epidemicin Mekambo (Grand Etoumbi, March 2002)(Fig. 1) was positive for EBOV-specific IgG,and EBOV virus sequences from the L genewere detected in bone-marrow samples of thegorilla identified as the source of thisoutbreak, conclusively linking the two cases.

Nucleotide sequence variations of the GPgene, distinct from those observed previouslyin humans, were also found in infected tis-sues from dead animals. We identified 11different EBOV strains from human and an-imal samples between October 2001 and May2003 in northern Gabon and in the regionbordering RC. Molecular analyses based onestimated nucleotide substitution rates indi-cate that the four known EBOV subtypesdiverged thousands of years ago and do notspread rapidly from one region to another ofthe central African forest block (16). A pre-vious study focusing on the most divergentregion of the GP gene shows that the EBOVisolates obtained from fatalities and survivorsduring the Kikwit outbreak in 1995 are ge-netically stable (17). Similarly, there were nonucleotide sequence variations in the GP andnucleoprotein genes among isolates from fa-talities, survivors, and asymptomatically in-fected individuals during the 7-month Gabonoutbreak in 19961997 (18). The same studyshows that the Booue sequence diverges fromthat of other Zaire subtype strains by only 1to 2% (36 substitutions of a 2174-nucleotidefragment), despite the 20-year interval and3000-km distance between the Booue 1996and Zaire 1976/1995 outbreaks. The veryhigh genetic stability of EBOV, and our find-ings of many different EBOV sequences that

Fig. 2. Immunohistochemical staining of Ebolaviral antigen in muscle of a dead gorilla. Viralantigens are seen in endothelial cells liningblood vessels. Naphthol fast red substrate withhematoxylin counterstain. Original magnica-tion 63.

Table 2. Gorilla, chimpanzee, and duiker population indices, used to estimate population densities, werecompared before (2000) and after (2003) the Ebola outbreak in the 320-km2 Lossi sanctuary area in theRepublic of Congo. See (12).

AnimalsIndices/kmin 2000

Indices/kmin 2003

Reductionrate (%)

Gorillas 1.69 0.74 56Chimpanzees 0.28 0.03 89Duikers 4.72 2.22 53

Table 3. Analysis of animal carcasses. Reverse transcription polymerase chain reaction (PCR), antigencapture (Ag), immunohistochemical (IHC) staining, and Ebola-specic IgG assays were performed aspreviously described (2022).

Animals Location Date Tissue PCR Ag IHC

Gorilla Gabon Nov 2001 Muscle Gabon Feb 2002 Bone marrow Gabon Feb 2002 Bone Gabon Feb 2002 Bone Lossi Dec 2002 Muscle Lossi Dec 2002 Muscle Lossi Dec 2002 Bone Lossi Dec 2002 Bone Lossi Feb 2003 Muscle Mbanza June 2003 Muscle

Chimpanzee Lossi Dec 2002 Muscle Lossi Dec 2002 Muscle Lossi Feb 2003 Muscle

Duiker Lossi Dec 2002 Bone Lossi Dec 2002 Bone Lossi June 2003 Skin

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do not vary during transmission along a givenhuman epidemic chain indicate that multipleindependent introductions of the virus fromits natural host to great apes had occurred.

Humans and duikers scavenging for meatprobably become infected by contact withdead apes. However, we found that animalcarcasses left in the forest are not infectiousafter 3 to 4 days (19). Therefore, virus trans-mission between different groups of apes isunlikely, because infectivity is short-livedand physical contact between individualsfrom different groups is rare. Different strainsof EBOV may be widespread throughout theforests of central Africa, with simultaneousinfection of great apes occurring from stillunknown natural hosts under particular butunknown environmental conditions. Ebolaoutbreaks in great apes have always beenreported at the beginning of the dry seasons(December 1995 in Mayibout, July 1996 inBooue, July 2001 in Mekambo, December2001 in Kelle, and December 2002 in thesecond Kelle outbreak). Thus, Ebola out-breaks probably do not occur as a singleoutbreak spreading throughout the Congo ba-sin as others have proposed (13), but are dueto multiple episodic infection of great apesfrom the reservoir.

The simultaneous occurrence of multipleepidemic chains in animals complicates thework of outbreak-response teams, becausenew cases may appear in unmonitored popu-

lations. Almost all human Ebola outbreaks inGabon and RC have been linked to the han-dling of dead animals by villagers or hunters,and increased animal mortality always pre-ceded the first human cases. A monitoringnetwork for large-animal mortality rates isneeded for rapid implementation of EBOVprevention measures when increased deathsare observed among wild animals living nearhuman communities.

References and Notes1. A. S. Khan et al., J. Infect. Dis. 179, (suppl. 1), S76

(1999).2. A. Sanchez, M. P. Kiley, B. P. Holloway, D. D. Auperin,

Virus Res. 29, 215 (1993).3. H. Feldmann, H. D. Klenk, A. Sanchez, Arch. Virol.

(suppl. 7), 81 (1993).4. A. J. Georges et al., J. Infect. Dis. 179, (suppl. 1), S65

(1999).5. K. M. Johnson, Bull. WHO 56, 271 (1978).6. D. I. H. Smith, Bull. WHO 56, 247 (1978).7. R. C. Baron, J. B. McCormick, O. A. Zubeir, Bull. WHO

61, 997 (1983).8. B. Le Guenno et al., Lancet 345, 1271 (1995).9. World Health Organization, Wkly. Epidemiol. Rec. 76,

41 (2001).10. E. M. Leroy, S. Souquie`re, P. Rouquet, D. Drevet,

Lancet 359, 712 (2002).11. P. Formenty et al., Med. Trop. 63, 291 (2003).12. Materials and methods are available as supporting

material on Science Online.13. P. D. Walsh et al., Nature 422, 611 (2003).14. P. Formenty et al., J. Infect. Dis. 179, (suppl. 1), S120

(1999).15. S. Baize et al., Nat. Med. 5, 1 (1999).16. Y. Suzuki, T. Gojobori, Mol. Biol. Evol. 14, 800 (1997).17. L. L. Rodriguez et al., J. Infect. Dis. 179, (suppl. 1),

S170 (1999).

18. E. M. Leroy, S. Baize, J. Lansoud-Soukate, E. Mavoun-gou, C. Apetrei, J. Gen. Virol. 83, 67 (2002).

19. E. M. Leroy, P. E. Rollin, unpublished data.20. E. M. Leroy et al., J. Med. Virol. 60, 463 (2000).21. T. G. Ksiazek et al., J. Clin. Microbiol. 30, 947 (1992).22. S. R. Zaki et al., J. Infect. Dis. 179, (suppl. 1), S36

(1999).23. The authors thank the national and international

teams involved in the control of the Ebola outbreaksthat occurred in Gabon and the Republic of Congo.The national teams were members of the GaboneseHealth Ministry and the Health Service of the Ga-bonese Defense Ministry during the Gabon outbreaks,and they were members of the Congolese HealthMinistry during the outbreaks in the Republic ofCongo. The international teams were mainly scien-tic and medical experts of the World Health Orga-nization (WHO) and Medecins Sans Frontie`res. Wethank all those involved in sample collection and casereporting. We are also grateful to A. Delicat, P. Yaba,B. Kumulungui, and G. Moussavou for excellent tech-nical assistance, D. Young and P. Telfer for help inpreparing the manuscript, D. Drevet and C. Avelingfor constant support and encouragement, and C.Chesley for editorial comments. Last, we thank T. G.Ksiazek from the Special Pathogens Branch of theCenters for Disease Control and Prevention, whogenerously provided reagents to the Centre Interna-tional de Recherches Medicales de Franceville(CIRMF). CIRMF is supported by the Government ofGabon, Total-Fina-Elf Gabon, and Ministe`re de laCooperation Francaise. This work was also supportedby a Fonds de Solidarite Prioritaire grant from theMiniste`re des Affaires Etrange`res de la France (FSPno. 2002005700).

Supporting Online Materialwww.sciencemag.org/cgi/content/full/303/5656/387/DC1Materials and MethodsTable S1References

14 October 2003; accepted 25 November 2003

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1www.sciencemag.org SCIENCE Erratum post date 30 JANUARY 2004

post date 30 January 2004

ERRATUMC O R R E C T I O N S A N D C L A R I F I C A T I O N S

RREEPPOORRTTSS:: Multiple Ebola virus transmission events and rapid declineof central African wildlife by E. M. Leroy et al. (16 Jan. 2003, p. 387).The GenBank accession number for the reference sequence used inthis paper was omitted. It is AY058898 for the GP gene from theBooue outbreak in Gabon in 1997. The GenBank accession numbersfor the additional sequences determined in this study are AY526098,AY526099, AY526100, AY526101, AY526102, AY526103, AY526104,and AY526105.